I got one of the garage door I/O Linc setups. Works fine. However, the readout on IndigoTouch is counterintuitive: because it is a normally closed switch (I think this is right) when the door is in the closed position, e.g. the magnet is next to the sensor, the sensor is held open (maybe that means it is normally open?). In any event, Indigo Touch tells me the garage door is OPEN whereas it is actually closed. Gives me a headache to think about it.

I found some 2 -1/2 inch active sensors at SmartHome that are normally open, so when the door would close, they would read closed. But, that means that 5v is always running thru the sensors. Does that matter?

...could I move a wire or something on the Garage Door sensor to make it a normally open sensor?

The terms normally-open (NO) and normally-closed (NC) refer to the state of the switch contacts in a relay/magnetic switch, etc when it is in the normal (i.e. not operated) condition. So, with a magnetic sensor, when it is not near the magnet (the "normal" case) a set of NO contacts would be open (not in contact). Then, when the switch came near the magnet the switch would close.

It is very common for relays, etc. to offer both NO and NC contacts. This lets you choose the way you wish the output to appear. This diagram of a NO magnetic switch provides a good illustration. Since it is being operated by the magnet, the NC lead is connected to the common. But, when the magnet is moved away, the NO contact will once again be connected to the common:

In your case, you would probably want to use the NO contacts of your garage door sensor. That way the I/O-Linc would report open when the door was in fact open and closed when the door was closed.

Very helpful, thank you both. The fixed door sensor has 3 wires, black, red and green. Not having played with these before, I just hooked up black and red, figuring the green was a ground - for what I didn't know. Anyway, I changed to the black and green, and it works like a charm. When the garage door is closed, the IO linc reports closed.

Also, I now understand what they mean by "normally" open or closed, e.g. the state of the sensor when the magnet is not near it.